Hydrocarbon oil composition



Patented July 7, 1953 2,644,795 1 HYDROCARBON OIL COMPOSITION- Joseph.E. Fields, Dayton, Ohio, assignor to Mon- 'santo Chemical-Company, St.I ouis', Mo., acorporation of Delaware No Drawing. ApplicationNovember-15,1950,

Serial No. 195,897-- I This invention relates to antifoaming hydrocarbonoils and deals more particularly with hy drocarbon oils containing, asanti-foaming agents, small amounts of certain ketonic esters;

The problem of foam inhibition is one of major 5 Claims. (01. 252-56)importance to all industries employing hydrocarbon oils underfoam-inducing conditions. While most oils will foam to some extent dueto vigorous agitation and aeration in a running engine, foaming becomesa problem only when loss of oil occurs by foam seepage or when somanyair bubbles are present in the oil that proper lubrication ofbearing surfaces is impeded. Foaming isv often experienced with dry sumpengines in which there is employed a scavenger pump for collecting oilfrom various engine parts and returning it to the lubricant reservoir.Here air maybe colv lected along with the oil and deposited in thereservoir. The design and operationof aircraft engines is such thatfoaming occurs more readily in this type of engine than it does inautomotive engines.

properties have been met by the formulationand use of numerous chemicalswhich give these desirable properties to oils when admixed therewith,the use ofsuch additives makes the treated oils particularly susceptibleto foaming. While light grade oils, e. g., SAE 10 grade oils, are almost1 1 non foaming under the 'most severe" conditions,

when there are employed with these oils oneor more additives such asviscosity index improvers, extreme pressure resisting improvers,pour-point depressors, etc. The resulting improved oils do not retaintheir non-foaming characteristics and are frequently even moresusceptible to foaming than are the heavygrade oils.

Hence, with the development of new high-speed engines and the provisionof the new additive-type lubricants, the problem of foaming has assumedmajor importance. Attempts to solve the problem Foam and froth inhydrocarbon oils, however,

is not due solely to engine design. Although lo-' cation and design ofthe oil pump, oil sump and oil lines as well as modification of othermechanical features may retard foam development, when certain oils areemployed with high speed engines, mechanical control, alone, does notsuffice. Herethe nature of crankcase oil is often the prime factor infoaming difiiculties. The heavier the grade of the oil or the higher thevis cosity of the oil, the more diiiicult it is to avoid foaming. Heavygrade oils-such as those employed in high-speed diesel and sparkignition engines operating under severe 'conditions'areparticularlysusceptible to foaming. The heavy oils holdbubbles very firmly so thatwhen foam is formed, it is very persistent. I

New developments in engine construction have constantly demandedlubricants having properties not possessed by crude hydrocarbon oils.Such properties are now generally imparted tolubricants by the use ofadditives. For example,"in order to satisfy the lubricationrequirementsof hypoid gears, materials which impart extremepressureresisting properties are now generally added to gear lubricants. In mostcases, however, the improvement attained in an oil by the use ofadditives is made only at the expense of increasing its susceptibilityto foam. Thus, while the demands of modern engine design for ex-' tremepressure resisting lubricants, for anticorrosive lubricants, forlubricantsof increased viscosity and low pour-point and good 'detersiveby defoaming existing oils, e. g., by submitting oils toheat-treatment,adsorption processes, filtering steps, etc, have proved of but littlevalue. The most practical solution to this problem has been made by theuse of anti-foam additives.

A number of anti-foam additives, i. e., antifoaming agents, foamdepressingagents, foam depressants, anti-frothe'rs'or' foam suppressors,

ar known; but in prior art their use has been attended with numerousdifliculties. Among disadvantages of such known additives are chemicalreactivity with the lubricant or other oil additives, corrosive effect,susceptibility to decomposition upon heating, instability when exposedfor long periods of time to ordinary atmospheric conditions, high cost,etc.

Now I havefound that foaming of hydrocarbon oils is efficiently retardedand even completely inhibited when there is added to such oils a smallquantity, say, up to 1.0 'per cent by weight of a liquidaddition productof one mole of a saturated al'dehyde of from 1 to 18 carbon atoms 7 Iwith more than'one mole of a trialkyl aconitate in which the alkylradical has from 1 to s carbon atoms. Addition products of this kind aredescribed in the copending application of Tracy M.

Patrick and Earl W. Gluesenkamp, Serial No.

195,915 filed November 15, 1950. They are readily obtained by afree-radical-catalyzed addition reaction spbstantially according to thescheme in which R is an alkyl radical of from 1 to 17 carbon atoms, Y isan alkyl radical of from 1 to 8 carbon atoms, and n is an integergreater than one. Saturated aldehydes which may be employed in preparingthe anti-foaming adducts are, for example, acetaldehyde,propionaldehyde, nbutyraldehyde, isobutyraldehyde, n-valeraldehyde,isovaleraldehyde, methylethylacetaldehyde, n-caproic aldehyde,isohexaldehyde, 2-ethylhexaldehyde, capric aldehyde, undecaldehyde,lauric aldehyde, palmitic aldehyde, stearic aldehyde, etc.

Aconitates which may be reacted with the above aldehydes to yieldaddition products having antifoaming properties are, for example,trimethyl, triethyl, triisopropyl, diethyl n-butyl, tri-sec.- butyl,tri-tert.-butyl, tri-n-amyl, methyl di-sec.-

amyl, tri-tert.-amyl, tri-n-hexyl, triisohexyl, 1311111- n-octyl,triisooctyl and tris(2-ethylhexyl) aconitate. A mixture of differentalkyl aconitates may be employed, e. g., a mixture of triethyl aconitateand trihex'yl aconitate to give adducts having recurring triethyl esterandtrihexyl ester units.

Preparation of the present liquid mixture of adducts may be effected bysimply contacting the saturated aldehyde with the aconitate inthepresence of a free-radical-1iberating agent such as a peroxidic compoundat ordinary or increased. temperature until formation of the adducts hasoccurred, andremoving from the resulting reaction mixture any unreactedstarting materials and 1:1 addition products.

The present aldehyde-aconitate adducts are effectiveanti-foaming agentswhen they are employed in very low proportions, i. e., in amounts of upto 1.0 per cent by weight, based on the weight of the total hydrocarbonoil composition. From .008 per cent to .05 per cent, of the adducts ispreferred, depending upon the nature of the oil. Heavy oilsand oilscontaining foam-inducing adjuvants require more of the presentantifoaming adducts than do base oils of good viscosity characteristics.

The anti-foaming effect of the aldehyde-aconitate adducts is notmaterially affected by the presence of other adjuvants in the oil. Thepresent adducts are stable keto-esters which can be hydrolyzed only withdifficulty, and since they are present in the oils in only very smallquantities, the use of even very acidic or very basic additionsin theoil has substantially no effect-on the adducts. Hyrocarbon oilscontaining the present antifoaming agents are stable when stored overlong periods of time and also when subjected to heat and pressureconditions of engine and motor operation,

While the antifoaming effect of the aldehyde aconitate adducts isobtained when they are employed in concentrations of up to 1.0% byweight, the adducts may be incorporated into hydrocarbon oils in muchhigher proportions, e. g., in amounts of up to 10 per cent or even 50per cent of the weight of the hydrocarbon oil to give concentrates. Oilscontaining such high proportions of the adducts may be manufactured andsold for use as lubricant additives. Addition of small amounts of suchconcentrate to hydrocarbon oils may be made so as to supply an oilcontaining suitable quantities of the adducts.

Hydrocarbon oils which are rendered substantially antifoaming byincorporation therein of quantities of up to 1.0 per cent of the presentadducts are synthetic or petroleum stocks of varying viscosities such aslubricating oils for internal combustion engines and motors, dieselfuels and lubricants and pressure transfer media, e. g., in-

dustrial lubricants, process oils, hydraulic oils, turbine oils, cuttingoils, fluid greases, gear oils, shock absorber oils, spindle oils,journal bearing oils, pneumatic tool lubricants, etc. They may besynthetic or natural hydrocarbons of any type, i. e., parafiinic,naphthenic or blended.

The invention is further illustrated, but not limited, by the followingexample Example The anti-foaming properties of lubricants may bedetermined according to the procedure generally described, inDesignation Ll2-445 of the Coordinating Lubricants Research Committee ofthe, Coordinating Research Council. New York. Briefly this procedureinvolves bubbling air or an inert gas such as nitrogen through thehydrocarbon oil to be tested, employing standard apparatus and standardconditions.

The oil was placed in a standard -ml. graduated cylinder in the top ofwhich was inserted a two-hole. rubber stopper. An air-inlet tubeextended through this stopper, to the bottom of which was attached a gasdiffuser or porous stone sphere. The length, of the inlet tube wasadjusted so thatwhen the apparatus was assembled, the sphere justtouched the bottom of the cylinder. The sphere was attached to the inlettube by means oflitharge and glycerine, or by a copper tube soldered tothe diffuser-stone coupling. The oil bath used was capable ofcontrolling temperature at 200:+;1 F. A93.3i0.6 C.), large enoughtopermit the cylinder to be immersed at least to the 90-ml. mark, andarranged to permit the visual observation of the graduations on thecylinder.

Dry nitrogen air was supplied at the rate of 0.2 cubic, foot per hour,employing a calibrated flowmeter. The. sample was heated to F. (48.9 C.)and then cooled, before testing, to 75i5 F. (23.9i2.8 C.) in aconstanttemperature room. 25 cc. of oil was used for each test.

With the air hose disconnected between the fiowmeter and the. deliverytube to the diffuser stone, the stone was allowed to soak in the oil for5 minutes, at the end of which time the air flow (0.2 .cu. ft. per hour)was started through the stone. Zero time was noted when the air ornitrogen bubbles started to rise from the stone. Readings of thetop andbottom foam levels were taken at the end of a 5-minute period. Thevolume of foam was calculated from the two readings.

Employing the testing procedure described above there was determined.the anti-foaming effeet of a liquid mixture of2-ethylhexaldehydetributyl aconitate adducts when added to a Champlin 30SAE base oil in concentrations of from 0.02% to 0.05% by weight of theoil. The liquid mixture of adducts. B. P. above 172 C./0.5 mm. n l.4556,was prepared by the addition reaction of 2eethylhexaldehyde withtributyl accnitate in the presence of benzoyl peroxide, as described inthe previously cited copending application. The following results wereobtained:

Concentration of adduct, weight Foam, cc. 0.02 10 0.03 none 0.05 none Inthe absence of an additive, the Champlin 30 SAE oil gave 71 cc. of foamunder the same testing conditions.

Non-foaming hydrocarbon oil compositions may be obtained byincorporating into such oils,

in a quantity of up to 1.0 per cent based on the Weight of thecomposition, other liquid mixtures of adducts of one mole of a saturatedaliphatic aldehyde with from 2 to 20 moles of trialkyl aconitates. Thusinstead of the 2-ethy1hexaldehyde-tributyl aconitate adducts employed inthe above example there may be used, e. g., adducts of 1 mole ofn-butylaldehyde, of acetaldehyde or of hexaldehyde with from 2 to 20moles of a trialkyl aconitate such as tri-n-amyl, triisopropyl ortri-whexyl aconitate. The present adducts impart anti-foaming propertiesto hydrocarbon oils, generally,'in the presence or absence of othercustomarily employed additives such as extreme-pressure resistingadditives, detergent additives, etc,

What I claim is:

1. A substantially foam-resisting hydrocarbon oil composition containingup to 1.0 per cent by weight, based on the weight of the composition, ofa liquid mixture of adducts having the formula in which R, is an alkylradical of from l-to 1'7 carbon atoms, Y is an alkyl radical of from 1to 8 carbon atoms and n is an integer of from 2 to 20.

2. A lubricant composition containing a hydrocarbon oil, and up to 1.0per cent by weight, based on the weight of the composition, of a liquidmixture of adducts having the formula in which R is an alkyl radical offrom 1 to 17 carbon atoms, Y is an alkyl radical of from 1 to 8 carbonatoms and n is an integer of from 2 to 20.

3. A lubricant composition containing a hydrocarbon oil and up to 1.0per cent by weight,

based on the weight of the composition of a liquid mixture of adductshaving the formula in which Bu denotes the butyl'radical, R is an alkylradical of from 1 to 1'7 carbon atoms, and n is an integer of from 2 to20. I

5. A lubricant composition containing a hydrocarbonoil and up to 1.0 percent by weight, based on the weight of the composition, of a liquidmixture of adducts having the formula 1 CHaCHgCH2CHCH2CO[-([DH (1) $112111 CHQCHQ COOBu COOBu oooBu in which Bu denotes the butyl radical and nis an integer of from 2 to 20.

JOSEPH E. FIELDS.

References Cited in the file Of this patent UNITED STATES PATENTS NameDate Gleason July 10, 1945 Borsofi; Oct. 31, 1950 Borsoff Oct. 31, 1950Grammaria Oct. 9, 1951 Bartlett Nov. 20, 1951 OTHER REFERENCES NumberFoaming of Aircraft-Engine Oils as a Problem in Colloid Chem. NACAreport ARR. No. 4 I 05- 1944-McBain et a1.

1. A SUBSTANTIALLY FOAM-RESISTING HYDROCARBON OIL COMPOSITION CONTAININGUP TO 1.0 PER CENT BY WEIGHT, BASED ON THE WEIGHT OF THE COMPOSITION, OFA LIQUID MIXTURE OF ADDUCTS HAVING THE FORMULA